Luffing crane



LUFFING CRANE Filed Sept. 28. 1 943 2 Sheets-Sheet 1- Feb 6, 1945. G. T. sHoosMrrH 2,368,391

LUFFING CRANE Filed sept. 28, 1943 2 sheets-Sheet 2 v TradE'fS Patented Feb. 6, 1945 shoosmith,

Application September 28, 19213', Ser'al'N. 504,'1'74` VIni-'Grr`aat-Britain January 20, `1943.

' comme.. (creiasof inA a .plane whichrcuts: thef crane' mast' o'r post i soi 1'0v that the jib.*cannot-.pass'fthe 'crane-'mastnon p'o'stand*v theloadizcannot :be: transfer-red Afromoneiside? toftherother: of theicrane simply` luflingthexjibi.

In; a. crane f according. tozfthe; presentiinvention;A the Yjibv and, its: pivot; are so' constructed and: arie:

ranged that the jib can bealuiedoriturnedaboutl l its pivot'. through an; arc fextendingyon'. each. side ofv thevertical plane' containing the: axistlof; the pivot*v and therheald) ofi the'iib`` during: the-.f luin'gf movements, instead of travellingrin ai vertioaii planewhich cutsf themast o'rpost; travelsinf ai plane whichisclear ofthe crane mastor posti so;

thaty the jibis.. not prevented from" b'eingz lui'edf from one sideof the crane to. theeother;`

In. order that the jib .head'sheave-mayproperlv support the hoisting-rope Ythroughoi-itthe yextended` luing movement of. the jibifromfoneextreme in-- clinedA position. toithgother. reverselyinclined p siton, .the axles of .the jib head. sl'eaveor sheaves and the mast -or p-ostheadfsheavepr sheaves' are:

carried bysWivelling forks `and the .jib headsheavef,

Inthe accompanyingrillustrative drawings, Figs.

l and2'are elevations at' right angles of a lufling and slewing crane according to the invention, the jib being shown in Fig. 1 luffed out and in Fig. 2 vertical in the plane of its pivot.

Fig. 3 is a plan view.

Fig. 4 is a diagrammatic View illustrating the arrangement of the ropes for obtaining level lufng of the load.

The crane structure a maybe arranged ona base b either xed or travelling of usual design. The base is shown provided with a bearing c for the foot of the structure a, a circular path or rail d for guide rollers e on the structure and a rack the axis of tnebearing beingtangentiartothe:

sheaves.

The iib k is mounted on a pivotkxioeataon the structure laterally ofthe mast or post portion a'.and'^radial to the axis'of' the'shank' ofthe forkv z`;the major axis-of' the jib lies' at an angle to thepivot'l and when the jib is luffed vertical in the plan'e ofitspivot (Fig: 2)' the jib" is clear of7 ingwhich"receivestheshank of ai swivelling VforklV that carries'a sheave mi forthe hoistin'grope n:

The' shank of the fork lisset at anangle ingthe jib head such that if :its axis`-wereextended it Would` cut the extended axisioi'the-Vshank of' the' fork `il' ori-thomas1;A or postal" at azpointfin lineWith' the axis of the jib pivot kx The forks and l arei c'onnectedbypairs of rods-oan'dfof" which are articulated "at the -one 'en'dto the respectivelforks atvthe-other endithe rods candidare respectively: provided? with, c'ro'ss .i members 'p andi.' pf' formedi with holes the rods o passing through thememf bersp' and therrods 'of 'passing lthrough the members?, p; Thisl arrangement. off swivellin'gi sheave? forks` and rods: permits*` the distance betweenthe" forksxi and Z tovar-y during lulng of: the jib.:

Whilst maintaining theiaxleaof thejib'head sheave` mfvirtually, horizontal fandfthe axles of the sheaves i and.l mf parallel softhat .the'hoist rope..l n: isxprop'ferly supported "on the sheaves: throughout the. luiing movementsiofthe jib..

'Other means for instance spur. gear, mayfbe?` used: toV cause. swivellingfoff. the jib. head fork.v corresponding to the movement of the jib;

The-jib -beyond its pivot istshown .provided-With` a balance `Weight ru and; W-itha circular rattlesv which is engaged by a spur gear t motor driven to effect lufling of the jib. Lufling `may be effected by other means for instance by a crank drive or by hydraulic ram or by means of ropes.

The hoist or load rope e passes from the sheave 1' down through the shank ofthe fork i round a sheave u (which may be xed or as shown attached to weighing gear v) on' the structure a, thence over a sheave w which is mounted to slide in guides to the hoisting drum y; the sheave w ismounted in a bridle z attached to a rope I which f engaged by a pinion g driven through gearing passes round fixed sheavesv 2 Aand 3,' up ,through the shank of the fork z', over a sheave 7" on the same axis as the sheave i and is secured to the member p of the rods vo. With suitable relative arrangement of the jib k andthe mast or post a level luing is thus provided for as any luiiing of the jibv alters the position of the sheave w andso compensates for variation in the vertical position of the load that would follow the raising and lowering of the sheave m. Other means of securing level lufng of the load may be used.

A suitable distance between the pivot Z and the Asheaves i 7" is about one third of the distance between the pivot kx and the sheaves m.

As will be seen from Fig. 1 the load can bel transferredl by lufling the'jib Without slewing the crane structure from the position shown in full lines on one side of the crane to the position shown in dotted lines on the other side of the crane, thus enabling the Working speed to be iny As will be understood, instead of a single load rope, a number of ropes or a set of grab-operating ropes can be used, the required number of sheaves being provided.

What I claim is:

'1. A lufng crane comprising a crane structure, a pivot on said structure, a jib on said pivot,.a post on said structure extending above said pivot, a sheave on said post, a second sheave on said jib, a. hoisting rope passing over said sheaves, the jib and its pivot being so arranged that the jib can be lufed or turned about its pivot through an Varc extending on each side of the Vertical plane containing the axis of the pivot, the head ofthe jib during the lung movements, instead of travelling in a vertical plane which cuts the mast or post, travelling in a plane which is clear of the crane mast or post.

v2. A lung crane according to claim 1 in Whic the post and jib sheaves are carried by swivelling forks and the axle of the jib sheave is maintained substantially horizontal Whatever the position of the jib.

3. A lufling crane according to claim 1 in which the jib pivot is located radially and laterally of the post' and the jib lies at an angle to the pivot and when luifed vertical in the plane of its pivot is clear of the mast or post. 1

4.` A luflng crane comprising a crane structure with mast or post and a jib pivoted to the structure, the jib and its pivot being so arranged that the jib can be luifed or `turned about its pivot through an varc extending on each side of the vertical plane containing the axis of the pivot, the head of the jib during the luflng movements, instead of travelling in a vertical plane which cuts the'mast or post, travelling in a plane which is 5. A luiing crane according to claim 1, in which the post and jib sheaves are carried by swivelling forks and the axle of the jib sheave is'maintained substantially horizontal Whatever the position of the jib, and in which the swivelling forks at the postand jib have articulated to them pairs of rods telescopically arranged but adapted to prevent relative rotary movement.

6. Ailufng crane comprisingv a crane structure with mast or post and a jib pivoted to the structure, the jib and its pivot being so arranged that the jib can beluifed or turnedabout its pivot through an arc extending on each side of the vertical plane containing the axis of the pivot, the head of the jib during the luimg movement,

'instead of travelling in a vertical plane Which cuts the mast orr post, travelling in a plane which is clear of the crane mast or post, a hoisting rope passing over'post and jib sheaves whichare carried by swivelling forks and the axle of the jib head sheave being maintained substantially horizontal Whatever the position of the jib, the swivelling fork of the jib sheave having its shank set at an angle such that if its axis were extended it Would cut thel extended axis of the shank of the post swivelling fork at a point in line with the axis of thejib pivot.

7..A lufling crane according to claim 1, in

which the post and jib sheavesare carried by swivelling forks and the axle of the jib sheave is maintained substantially horizontal Whatever the position of the jib, and in which the swivelling y forks at the post and jib have articulated 'to them Ypairs of rods telescopically arranged but adapted to prevent relative rotary movement, the pair of rods articulated to the jib swivelling fork being connected to a rope which passes over sheaves and, 

